I don't believe that any option is off the table so this is obviously a possibility. Grace may be right that atm they're thinking about killing off T'Challa though I doubt there aren't other plans being floated where he continues on. I've seen commentators confirm the latter and I don't believe them either. It's only been about 2 months since Boseman's passing, Disney hasn't figured out what they want to do yet. And as public opinion (as seen in that link) continues to shift towards keeping the character alive then who knows what the executives will be thinking 5 months from now?